“OM” in optical communication refers to “Optical Multi-mode”. Optical mode, which is a standard for multimode fiber to indicate fiber grade. Currently, TIA and IEC defined fiber patch cord standards are OM1, OM2, OM3, OM4, and OM5.
First of all, what is multimode and single mode?
Single Mode Fiber is an optical fiber that allows only one mode of transmission. The core diameter is about 8 to 9 μm and the outer diameter is about 125 μm.Multimode Optical Fiber allows different modes of light to be transmitted over a single fiber with a core diameter of 50 μm and 62.5 μm. Single-mode fiber supports longer transmission distances than multimode fiber. In 100Mbps Ethernet to 1G Gigabit, single-mode fiber can support transmission distances over 5000m. Multimode fiber is only suitable for medium and short distance and small capacity fiber optic communication systems.
What are the difference between OM1, OM2, OM3, OM4, OM5?
In general,OM1 is conventional 62.5/125um.OM2 is conventional 50/125um; OM3 is 850nm laser-optimized 50um core multimode fiber. In 10Gb/s Ethernet with 850nm VCSEL, the fiber transmission distance can reach 300m.OM4 is an upgraded version of OM3. OM4 multimode fiber optimizes the differential mode delay (DMD) generated by OM3 multimode fiber during high-speed transmission. Therefore, the transmission distance is greatly improved, and the fiber transmission distance can reach 550m. The OM5 fiber patch cord is a new standard for fiber patch cords defined by TIA and IEC with a fiber diameter of 50/125 μm. Compared to OM3 and OM4 fiber patch cords, OM5 fiber patch cords can be used for higher bandwidth applications.The bandwidth and maximum distance are different when transmitting at different levels.
What is an OM5 fiber patch cord?
Known as Wideband Multimode Fiber Patch Cable (WBMMF), OM5 fiber is a laser-optimized multimode fiber (MMF) designed to specify bandwidth characteristics for wavelength division multiplexing (WDM). The new fiber classification method is designed to support a variety of “short” wavelengths between 850 nm and 950 nm, which are suitable for high bandwidth applications after polymerization. The OM3 and OM4 are designed primarily to support a single wavelength of 850 nm.
What is the difference between OM3 and OM4?
1.Different jacket color
In order to distinguish between different fiber jumpers, different colors of the outer sheath are used. For non-military applications, single mode fiber is typically a yellow outer jacket. In multimode fiber, OM1 and OM2 are orange, OM3 and OM4 are water blue, and OM5 is water green.
2.Different application scope
OM1 and OM2 have been widely deployed in buildings for many years, supporting Ethernet transmissions up to 1GB.OM3 and OM4 fiber optic cables are typically used in data center cabling environments to support 10G or even 40/100G high-speed Ethernet paths.Designed for 40Gb/s and 100Gb/s transmission, the OM5 reduces the number of fibers that can be transmitted at high speeds.
OM5 multimode fiber features
1. Fewer fibers support higher bandwidth applications
The OM5 fiber patch cord has an operating wavelength of 850/1300 nm and can support at least 4 wavelengths. The typical operating wavelengths of OM3 and OM4 are 850 nm and 1300 nm. That is to say, the traditional OM1, OM2, OM3, and OM4 multimode fibers have only one channel, while the OM5 has four channels, and the transmission capacity is increased by four times.Combining short-wavelength division multiplexing (SWDM) and parallel transmission technology, OM5 only requires 8-core wideband multimode fiber (WBMMF), which can support 200/400G Ethernet applications, greatly reducing the number of fiber cores. To a lesser extent, the wiring costs of the network are reduced.
2.Farther transmission distance
The transmission distance of OM5 fiber is longer than that of OM3 and OM4. The OM4 fiber is designed to support a length of at least 100 meters with a 100G-SWDM4 transceiver. But OM5 fiber can support up to 150 meters in length with the same transceiver.
3.Lower fiber loss
The attenuation of the OM5 broadband multimode cable has been reduced from 3.5 dB/km for the previous OM3, OM4 cable to 3.0 dB/km, and the bandwidth requirement at 953 nm has been increased.
The OM5 has the same fiber size as OM3 and OM4, which means it is fully compatible with OM3 and OM4. It does not need to be changed in the existing wiring application OM5.
OM5 fiber is more scalable and flexible, enabling higher speed network transmission with fewer multimode fiber cores, while cost and power consumption are much lower than single mode fiber.Therefore, the future will be widely used in 100G/400G/1T ultra-large data centers.